Vice President Joe Biden delivers remarks during the 9/11 ceremony at the Pentagon, Sept. 11, 2011, to remember the 184 people killed in the building and aboard American Airlines Flight 77 in a terrorist attack 10 years ago. DOD photo by R.D. Ward(Click photo for screen-resolution image);high-resolution image available.

Many of the estimated 1,300 people who gathered near the spot where a hijacked airliner slammed into the building were family members of the 184 people who died there Sept. 11, 2001.

“I know … as you sit here right now, unlike a month ago, everything has come back in stark relief,” Biden said to the families at the Pentagon’s 9/11 Memorial. “It’s not a thought. It’s precise. You remember that God-awful empty feeling, … that feeling of hollowness.”

The families of the nearly 3,000 people who died in the 9/11 attacks give hope to thousands of other Americans who also have suffered loss, the vice president said.

“You let them know that hope can grow from tragedy, and that there can be a second life,” he said.

Milestones such as today’s anniversary “compel us to reflect and to remember, to honor and, with God’s help, to heal, because that's what this is ultimately about,” Biden said.

The vice president described some of those killed at the Pentagon 10 years ago: “A Marine who lost his leg, and nearly his life, in Vietnam but who used what he called a ‘second chance’ to become a father of five; a 3-year-old passenger aboard that fateful flight, who held her stuffed ‘lambie’ each night, as her parents read her bedtime stories; the secretary who worked for American Airlines for 45 years, whose colleagues considered her a second mother, and who dressed as Mrs. Claus each Christmas; the Navy physicist, whose wife said after his death: ‘He was a wonderful dancer. I’ll never be able to dance with anybody else. He was a perfect partner. And above all, he was a good, caring and loving man.’”

They and thousands of other people are being remembered in towns and cities across America today, Biden said.

“But nowhere are the memories more immediate, more vivid, more compelling, more real than in New York City; Shanksville, Pa., and right here in northern Virginia at the Pentagon,” he added.

Recalling not only that day’s horror, but also the heroism it evoked, he said, “can hopefully give you some comfort and stiffen the resolve of this nation.”

Those who worked in the building, and thousands of first responders across the region, sprang to action, the vice president said, risking their lives so others -- friends, colleagues or total strangers -- might live.

“From corporals to cafeteria workers, right up the chain of the command to the top brass, to Secretary [Donald] Rumsfeld, … streamed into that breach between the 4th and 5th corridors, where the devastation was the greatest, where death came in an instant, but also where there were survivors to be found,” Biden said.

It’s a basic American instinct to respond in crisis, Biden said.

That instinct, he said, “echoes through the ages -— from Pearl Harbor to Beirut, from Mogadishu to ground zero, [from] Flight 93 to right here in the Pentagon.”

That same American instinct, he said, galvanized what he called “an entire new generation of patriots —- the 9/11 Generation.”

“Many of them were just kids on that bright September morning,” he said. But like their grandparents during World War II, he added, “they courageously bore the burden that history had placed on their shoulders.”

As they came of age, they showed up to fight for their country, “and they're still showing up,” he said.

“Two million, eight hundred thousand of that 9/11 Generation moved to join our military since the attacks on 9/11, to finish the war begun here that day,” Biden noted. They joined knowing that they were likely to be deployed in harm’s way, in Afghanistan and Iraq and other dangerous parts of the world, he said.

Biden said leaders such Mullen “turned this … 9/11 Generation into the finest group of warriors the world has ever known.”

“Over a decade at war, they pioneered new tactics, mastered new languages, developed and employed advanced new technologies,” the vice president said.

Today’s forces take on sobering responsibilities early in their careers, Biden said -- responsibilities extending to the politics and economies of Afghanistan and Iraq, and to “the development tasks that ultimately will lay the groundwork for us to leave behind stable countries that will not threaten us.”

Defense, intelligence and law enforcement forces “relentlessly took the fight to al-Qaida and its affiliates,” he said. “They were prepared to follow bin Laden to hell’s gate if necessary. And they got him.”

The 9/11 Generation has paid an incredible price, the vice president told the audience: 4,478 troops killed in Iraq, 1,648 who have died in Afghanistan, and more than 40,000 wounded in both countries.

“Having visited them multiple times like many of you, I am awed not only by their capability, but their sacrifice today and every day,” he said.

The terrorists who attacked the Pentagon sought to shatter the defining symbol of America’s military might, Biden said.

“But they failed,” he added. “They failed because they continue to fundamentally misunderstand us, as they misunderstood us on that day. For the true source of American power does not lie within that building.”

Americans draw their strength from “the rich tapestry of our people,” he said.

“Our spirit is mightier, the bonds that unite us are thicker, and [our] resolve is firmer than the million tons of limestone and concrete that make up that great edifice behind me,” he added.

The terrorists who attacked America never imagined that the 3,000 people who were killed “would inspire 3 million to put on the uniform, and harden the resolve of 300 million Americans,” the vice president said.

Speaking again to the families, Biden said, “My prayer for you is that, 10 years later, when you think of them, that it brings a smile to your lips before it brings a tear to your eye.”

The vice president said his thoughts and prayers, and those of his wife, Dr. Jill Biden, also are with the nearly 80 American service members and eight civilians wounded, and the two Afghan civilians – one a 3-year-old girl – killed in yesterday’s truck bombing in eastern Afghanistan’s Wardak province.

The attack is “a stark and vivid reminder this war continues,” Biden said. “The courage, determination and the sacrifices of our forces in Afghanistan and around the world is literally astounding.”

Biden said his mother used to say that courage lies in every heart.

“Here, on Sept. 11, 2001, at exactly 9:37 a.m., it was summoned,” he said. “It was summoned from the hearts of the thousands of people who worked here to save hundreds. It was summoned in the hearts of all those first responders who answered the call. For courage lies deepest in and beats the loudest in the heart of Americans.”